Re: [PATCH v12 6/8] sched/fair: Add sched group latency support

[Vincent Guittot]

On Mon, 27 Feb 2023 at 15:42, Michal Koutný <mkoutny@xxxxxxxx> wrote:
>
> On Mon, Feb 27, 2023 at 02:44:22PM +0100, Vincent Guittot <vincent.guittot@xxxxxxxxxx> wrote:
> > Regarding the current use of latency nice to set a latency offset, the
> > problem doesn't appear because latency offset applies between entities
> > at the same level as you mentioned above
>
> Splendid, it turned out that way (latency nice analogous to bandwidth
> nice).
>
> > Does  my explanation above make sense to you ?
>
> Yes, thank you.
>
> Thus, I'd like to propose avoiding the use of "limit" in this context and
> stress the horizontal scope. For example:
>
> > +     This interface file allows reading and setting latency using the
> > +     same values used by sched_setattr(2). The latency_nice of a group is
> > +     used to limit the impact of the latency_nice of a task outside the
> > +     group.
>
> +     This interface file allows reading and setting latency using the
> +     same values used by sched_setattr(2). The latency_nice of a group is
> +     used to modify group members' latency with respect to sibling groups.

That sounds reasonable to me.

>
> Regards,
> Michal